OBJECTIVE: The goal of the proposed research project is to continue an investigation of a method which may be useful in preventing loss of vision from glaucoma. This will be accomplished by design of a technique for precise measurement of the contour of the optic disc. The key element in the proposed study is the projection of a pattern of light onto the optic disc to define its surface. The technique now being investigated will be systematically refined and an error analysis of the results completed. Then, this method will be applicable in other studies and in glaucoma clinics generally to eyes which are considered by other clinical parameters "at risk" for glaucoma visual field loss: "ocular hypertensives" and patients under treatment to prevent onset or progression of glaucoma visual field defects. In other words, once proven, this may function as a predictor of field loss in the "glaucoma suspect" and as a monitor of adequacy of treatment in patients in whom the diagnosis has been established. METHOD: Light stripes are projected onto the human optic disc and an image of the disc is recorded photographically. Quantitative contour information is then derived from the course of the stripes as they follow the surface of the disc - the optical sectioning technique.